Dental implant

ABSTRACT

An implant is loosely inserted in an opening in the bone. A packing composition and/or growth factor is inserted in the opening to anchor the implant in the opening.

This is a continuation of application Ser. No. 08/087,185, filed Jul. 2,1993, now U.S. Pat. No. 5,397,235, which is a continuation-in-part ofapplication Ser. No. 08/053,886, filed Apr. 27, 1993, now U.S. Pat. No.5,372,503, which is a continuation-in-part of application Ser. No.07/877,132, filed May 1, 1992, now U.S. Pat. No. 5,378,152.

This invention relates to a method and apparatus for installing a dentalimplant in the alveolar or basal bone of a patient.

More particularly, the invention relates to a method and apparatus for adental implant which reduces the likelihood of the implant becominginfected, which does not require an opening of precise size to bedrilled or formed in the alveolar bone to receive the dental implant,which can mount an implant on existing alveolar bone without requiringalteration of the structure of the bone, which prevents the juncture ofthe dental implant and artificial tooth attached to the implant frombeing exposed in the event the patient's gums recede, which enables bonemass lost as the patient ages to be replaced, and which enables animplant to be used when drilling an opening in the alveolar bone isprecluded due to the existence of a nerve in the bone.

Dental implants are well known in the art. See, for example, U.S. Pat.Nos. 5,006,070 to Komatsu, 4,693,686 to Sendax, 4,812,120 to Flanagan etal., 4,818,559 to Hama et al., 4,671,768 to Ton, and 4,175,565 toChiarenza et al. Such prior art dental implants and methods forinstalling the same have disadvantages.

First, the implants normally must be press fit or wedged into an openingformed in the alveolar bone. Force fitting an implant into the alveolarbone is not desirable because it is uncomfortable for the patient, runsthe risk of cracking the jaw bone, further damages the bone, and, mostimportantly, increases the likelihood of infection because dentalimplants ordinarily are provided with an assortment of ridges, points,or teeth which serve as desirable sites for bacteria, both before andafter the implant is inserted in the bone. As a consequence, dentalimplants typically appear medieval.

Second, force fitting an implant in the alveolar bone requires that theopening formed in the bone have a specific size which roughly conformsto the outer dimensions of the implant so the implant can be force fitinto the opening. If a dental surgeon selects a drill of improper size,or waggles the drill while forming the hole in the alveolar bone, theimplant may not seat properly in the bone and will work free from thejaw.

Third, the surface area of the portion of the implant imbedded in thejaw is typically reduced because of the common belief that fenestrationsof various size must be formed in the implant to permit bone to growthrough and anchor the implant.

Fourth, conventional implant procedures often can not be used becausethe drilling of a opening in the alveolar bone is prohibited by a nervewhich passes through the bone.

Fifth, conventional implant procedures also often can not besuccessfully used when the jaw bone has significantly receded, as can bethe case with older patients.

Sixth, conventional implant procedures do not offer a way of replacingalveolar bone which has been lost due to aging or to some other causeresulting in injury to the bone.

Seventh, conventional implant procedures typically do not permit theready adjustment of the position of the implant after the implant isinserted in the opening formed in the alveolar bone. Correcting theposition of an improperly installed implant is often difficult, unlessthe implant is completely removed from the alveolar bone, which is atime consuming process.

Accordingly, it would be highly desirable to provide an improved dentalimplant method and apparatus which would not require the force fittingof an implant in the alveolar bone, would not require the formation of aspecific size opening in the jaw bone, would provide an implant lesslikely to loosen after being inserted in the alveolar bone, would permitan implant to be used on alveolar bone housing a nerve, would enableimplants to be successfully utilized on alveolar bone which has recededwith age, and would permit the position of the implant to be readilyadjusted after the implant is inserted in an opening in the alveolarbone.

Therefore, it is a principal object of the invention to provide animproved dental implant method and apparatus.

Another object of the invention is to provide an improved dental implantwhich can be inserted in an opening in the alveolar bone withoutrequiring that the opening must, within close tolerances, have aspecific shape and dimension.

A further object of the invention is to provide an improved dentalimplant which permits ready adjustment of the position of the implantafter the implant is placed in an opening formed in the jawbone.

Still another object of the invention is to provide a dental implantmethod which permits an implant to be attached to alveolar bone housinga nerve.

Yet a further object of the invention is to provide a dental implantmethod which allows an implant to be utilized on alveolar bone which hasexperienced significant loss and recession of its mass.

Another and further object of the instant invention is to provide animproved dental implant which is less likely to loosen after insertionin the alveolar bone.

These and other, further and more specific objects and advantages of theinvention will be apparent to those skilled in the art from thefollowing detailed description thereof, taken in conjunction with thedrawings, in which:

FIG. 1 is a front view of a dental implant apparatus constructed inaccordance with the principles of the invention;

FIG. 2 is a section view of the dental implant apparatus of FIG. 1illustrating internal construction details thereof;

FIG. 3 is a side view of a portion of the lower jaw bone illustratingthe implant of FIG. 1 installed in an opening formed in alveolar bone;

FIG. 4 is a top view of a portion of the jaw bone of FIG. 3 furtherillustrating the installation of the implant of FIG. 1 therein;

FIG. 5 is a perspective view illustrating a sheet of protective materialused to shield hydroxyapatite composition used to pack an implant intoan opening in the alveolar bone;

FIG. 6 is a top view of a portion of the lower jaw bone illustrating theinsertion of an implant in an opening formed by laterally drilling intothe jaw bone;

FIG. 7 is a side view of the jaw bone of FIG. 7 further illustrating thelateral opening formed in the jaw bone;

FIG. 8 is a side partial section view illustrating an alternateembodiment of the implant of the invention inserted in an opening formedin the alveolar bone;

FIG. 8A is a side view illustrating a portion of the implant of FIG. 8after the healing cap is removed;

FIG. 9 is a perspective view illustrating a healing cap used in theimplant of FIG. 8;

FIG. 10A is a side section view illustrating normal alveolar bonestructure around an incisor tooth;

FIG. 10B is a side section view illustrating the recession of thealveolar bone structure from around the incisor tooth of FIG. 10A;

FIG. 10C is a side view illustrating the insertion of an implant in thebone structure of FIG. 10C after the incisor tooth is removed or fallsout;

FIG. 10D is a side view illustrating the alveolar bone structure of FIG.10B after the incisor tooth is removed and a circular drill is used tocut away some of the alveolar bone to form a cylindrical anchor peg;

FIG. 10E is a side partial section view illustrating a dental implantslidably installed on the anchor peg of FIG. 10D and packed with amalleable hydroxyapatite composition;

FIG. 10F is a side partial section view illustrating the alveolar bonestructure of 10B after the incisor tooth is removed and an implant isslid onto the existing alveolar bone structure without altering thestructure;

FIG. 11 is a perspective view illustrating an implant of the type whichcan be fit to an existing alveolar bone structure;

FIG. 12 is a side partial section view illustrating a molding procedureutilized in another embodiment of the invention;

FIG. 13 is a perspective view of a sacrificial coping utilized in theembodiment of the invention illustrated in FIG. 12;

FIG. 14 is a perspective view illustrating another step in the moldingprocedure of FIG. 12;

FIG. 15 is a perspective view illustrating a finished dental bridgeproduced according to the method of FIGS. 12 and 14;

FIG. 16 is a side partial section view illustrating an artificial toothremovably attached to an implant apparatus;

FIG. 17 is a side partial section view illustrating a hip implantprocedure;

FIG. 18 is a partial side section view illustrating an interlockingopening formed in bone during an implant procedure according to theinvention;

FIGS. 19 to 21 illustrate an alternate implant procedure in accordancewith my invention; and,

FIG. 22 illustrates another embodiment of the invention.

Briefly, in accordance with my invention, I provide an improved dentalimplant. The implant comprises a body having a closed top and a bottomand a longitudinal axis extending through the top and bottom; and, ahead supported on the top of the body and adapted to support anartificial tooth. The body extends downwardly from the top andterminates at a lower end remote from the head. The body includes asmooth continuous surface extending from the top to the bottom anddefining the periphery of the top and the bottom. The smooth surfacecircumscribes the longitudinal axis. The body also includes a hollowcentrally defined therein, circumscribed by the continuous surface, andextending into the body through the bottom a selected distance towardthe top. The hollow only opens at the lower end of the body. The headcan have a smaller width than the body. The hollow can be an involute.The continuous surface can be shaped such that when any cross section ofthe body is taken perpendicular to the longitudinal axis, each point onthe continuous surface is generally equidistant from the longitudinalaxis.

In another embodiment of the invention, I provide a method of anchoringa dental implant in the alveolar bone of a patient. The method comprisesthe steps of forming an opening in the alveolar bone; inserting a dentalimplant in the opening, the implant comprising a body and a headsupported on the body and adapted to support an artificial tooth, thedental implant only partially filling the space in the opening; and,packing the space in the opening which is unoccupied by the dentalimplant with a hydroxyapatite composition. The opening can be largeenough to permit the implant to be readily tilted from side to sideafter insertion in the opening. After the opening is packed withhydroxyapatite composition, the implant can be adjusted or tilted fromside to side and the hydroxyapatite composition then repacked.

In a further embodiment of the invention, I provide a dental implantcomprising a body; a head supported on the body and having alongitudinal axis and including an upper portion adapted to support anartificial tooth and having a distal tip and a peripheral surfacecircumscribing the longitudinal axis and extending downwardly from thedistal tip toward the body, and, a lower portion supported on the body;and, a healing cap. The healing cap is adapted to be removably attachedto the upper portion of the head and includes a prophylactic portionwhich, when the healing cap is attached to the upper portion, slidablyextends downwardly from the tip over and covers at least a portion ofthe peripheral surface such that when the implant is inserted in anopening in the alveolar bone, a solidified filler composition at leastpartially fills the opening, extends downwardly from the distal tiptoward the body, and covers the prophylactic portion, the lower portion,and the body, and the healing cap is removed from the head, a spaceexists intermediate the portion of the peripheral surface and thesolidified filler composition such that an artificial tooth can extendinto the space and cover the distal tip of the head. The fillercomposition can be a hydroxyapatite composition.

In still another embodiment of the invention, I provide a method ofanchoring a dental implant to the alveolar bone of a patient. The methodcomprises the steps of placing the dental implant at a selected site onthe alveolar bone, the dental implant comprising a body and a headsupported on the body and adapted to support an artificial tooth;packing a malleable hydroxyapatite composition around the dental implantand against alveolar bone of the patient; and, covering the malleablehydroxyapatite composition with a pliable sheet of material to at leastpartially prevent gum tissue from growing into the hydroxyapatitecomposition while the hydroxyapatite composition solidifies.

In yet another embodiment of the invention, I provide a dental implantfor a ridge of alveolar bone normally at least partially covered by gumtissue. The implant comprises a body having a top and a pair of opposedfeet each extending downwardly from the top to a tip at a lower endremote from the top, the feet having an inner surface shaped, contoured,and dimensioned to conform to the ridge of alveolar bone when the gumtissue is removed from the ridge; and, a head supported on the body andadapted to support an artificial tooth.

In yet still another embodiment of the invention, I provide a method ofanchoring a dental implant to the existing alveolar bone of a patient,the bone having an existing outer surface. The method comprises thesteps of removing alveolar bone to form an outwardly projecting anchorpeg having a selected shape and dimension; and, inserting a dentalimplant over the anchor peg. The dental implant comprises a body and ahead support on the body and adapted to support an artificial tooth. Thebody extends downwardly from the head to a lower end remote from thehead and having an aperture formed in the lower end. The aperture isshaped and dimensioned to be slidably inserted on and conform to theoutwardly projecting anchor.

Turning now to the drawings, which depict the presently preferredembodiments of the invention for the purpose of illustrating thepractice thereof and not by way of limitation of the scope of theinvention and in which like reference characters refer to correspondingelements throughout the several views, FIG. 1 illustrates dental implantapparatus which is constructed in accordance with the principles of theinvention and includes a dental implant which has the general shape of awine bottle and includes a cylindrical head 10 attached to a body 11.The closed top 12 of body 11 has a smooth continuous conical outersurface which tapers from the smooth continuous outer cylindricalsurface 14 of the bottom 11 into the smooth cylindrical outer surface 13of head 10. The conical outer surface of top 12, as do smoothcylindrical surfaces 14 and 13, completely circumscribes longitudinalaxis and centerline 18. Head 10 can, if desired, be bent at someselected angle with respect to axis 18 and body 11 as indicated bydashed lines LOB or can be tapered in the manner of head 10A in FIG. 12.The bottom of body 11 extends downwardly from the top 12 and terminatesat lower end 17 remote from the head 10. Involute or hollow 15 is formedcentrally within body 11, is circumscribed by continuous surface 14, andextends upwardly into body 11 a selected distance toward top 12. Hollow15 opens only at the lower end 17. Head 13 has a smaller diameter thanbody 11. An internally threaded aperture 19 is formed in head 13 toreceive the externally threaded end 20 of a healing cap. Thefrustroconical head 21 of the healing cap has a cylindrical aperture 22formed therein. Cylindrical member 23 is attached to pliable fabricsheet 24 and is shaped to be removably snap fit into aperture 22. Thesheet 24 can be secured to the healing cap or head 10 using anyconvenient means. For example, an aperture 25 can be formed through apliable sheet 24A and sized such that end 20 slides through aperture 25and permits sheet 24A to be compressed between head 21 and the circulardistal end 26 of head 10. Rib 16 outwardly depends from the smoothcylindrical wall circumscribing and defining hollow 15 and, when hollow15 is filled with hydroxyapatite or bone in a manner which will bedescribed, prevents the dental implant from rotating about axis 18. Mostinfection in a tooth begins at the gum line and works its way downwardlytoward the root of the tooth. The smooth continuous outer surfaces 13,14 of the implant of FIG. 1 facilitate determining how far, if at all,infection has penetrated downwardly along the outer surfaces of theimplant. The extension of the outer surfaces of the implant from thedistal end 26 of the head to the lower end 17 make it difficult forinfection to enter hollow 15. In many conventional implants, onceinfection extends a short distance into the bone, it is a simple matterfor the infection to spread laterally under portions of the implant.Consequently, in the implant of FIG. 1 it is important that perforationsare not formed through the continuous outer surfaces 13, 14, or theconical surface of top 12. The large area of surfaces 13 and 14 and ofthe outer conical surface of top 12 help distribute the forces which areproduced on an artificial tooth mounted on the implant and decrease thelikelihood that the implant will come loose. The smooth curvature andlack of ridges or points extending outwardly from implant surfaces 13and 14 also decreases the likelihood that stress fractures will beformed in the alveolar bone during the use of an artificial toothattached to the implant.

The installation of the implant apparatus of FIGS. 1 and 2 in alveolarbone is illustrated in FIGS. 3 and 4. As shown in FIG. 4, an opening 27is drilled or otherwise formed at a selected location in the alveolarbone and the dental implant is inserted in opening 27. FIG. 4illustrates opening 27 immediately after the dental implant has beeninserted therein. Opening 27 is larger than the dental implant so thatthe head 10 can be grasped manually or with a dental instrument andtilted from side to side in opening 27. The space between the dentalimplant and the sides of opening 27 which circumscribe the implant ispacked with a malleable hydroxyapatite composition 28. Hollow 15 canalso be packed with the hydroxyapatite composition 28 before the implantis inserted in opening 27. After the composition 28 is packed intoopening 27 around the dental implant, the head 10 can, if desired, belaterally moved in directions like those indicated by arrows A to tiltand reposition the implant in opening 27. After the dental implant is inthe desired position in opening 27, the hydroxyapatite composition isrepacked, and member 23 is snapped into aperture 22 in head 21 toposition sheet 24 over opening 27 in the manner illustrated in FIG. 3.Sheet 24 can be trimmed as appropriate to cover opening 27. Although notshown in FIG. 4, gum tissue ordinarily at least partially covers andhelps maintain sheet 24 in its desired position. Sheet 24 can compriseGORTEX or any other suitable pliable material which helps prevent gumtissue from growing into the hydroxyapatite composition while itsolidifies. If desired, sheet 24 can comprise a resorbable material. TheGORTEX is left in place for a period of two to twelve months while thesurrounding bone grows into and causes the hydroxyapatite composition tosolidify and anchor the dental implant in place. After thehydroxyapatite composition has solidified, the healing cap and the sheet24 are removed such that the gum tissue covers the solidifiedhydroxyapatite composition. The internally threaded aperture 19 in thehead 10 of the implant is used to attach an artificial tooth to theimplant.

GORTEX is produced by W. L Gore & Assoc., Inc. Regenerative Technologiesof 3773 Kaspar Avenue, Flagstaff, Ariz. 86003-2500, USA. If desired, apliable sheet 24A can include a layer of GORTEX or similar pliablematerial laminated with an undercoating of collagen, polyglycolic acid,or another desired material. The collagen imparts a stiffness to sheet24A and over time is gradually dissolved by the body. GORTEX is anexpanded polytetrafluroethylene (e-PTFE) material.

Hydroxyapatite is a crystalline substance containing calcium andphosphorus and is found in certain rocks. It is the basic constituent ofbone. The hydroxyapatite composition used to pack opening 27 can simplycomprise a dry hydroxyapatite powder. The hydroxyapatite is, however,normally mixed with a liquid substance to form a slurry or moremalleable composition which is more readily packed and remains in fixedposition than dry hydroxyapatite powder. Hydroxyapatite powder can bemixed with water, plaster, collagen, dextran, epinephrine, or some otherdesirable material. The hydroxyapatite can be obtained from naturalmineral sources, from ground bone, etc. Materials other thanhydroxyapatite compositions can be used to fill and pack opening 27.Such other materials can include organic and inorganic matrices and/orcombinations thereof. These matrices can be porous, non-porous, activeand/or resorbable matrices, or totally inert. For example, coral andcoral analogs, polymethyl methacrylate, polyethylene, PTFE(polytetrafluroethylene), polysufone, polymers, polyethylene glycols,osteomin (bone ash), autogenous bone, freeze dried demineralized bone,resorbable and non-resorbable hydroxyapatite, xenographs (bovine),miniscrews, allografts, composites, polyethylene glycol propionaldehyde,HAPSET, or the patient's own bone can be utilized.

In some cases, it is preferable to produce an opening for a dentalimplant by forming an aperture in the alveolar bone which openslaterally or outwardly away from the inside of the patient's mouth. Suchan outwardly opening aperture 32 is illustrated in FIGS. 6 and 7. InFIG. 7, the dental implant has not yet been inserted on floor 33 ofaperture 32. FIG. 6 illustrates the implant in aperture 32. A malleablehydroxyapatite composition is utilized to pack the dental implant inaperture 32. Once aperture 32 is packed with hydroxyapatite compositionand the implant is properly positioned in the hydroxyapatite compositionand aperture 32, a healing cap is used to attach a pliable layer 24 ofmaterial to head 10 to protect the hydroxyapatite composition frominvasion by epithelial or other living tissue while the compositionhardens. After an appropriate period of time has passed and the bone hasgrown into and hardened the hydroxyapatite composition, the healing capand layer of material are removed and an artificial tooth is attached tohead 10 using internally threaded aperture 19.

An alternate embodiment of a healing cap 34 is illustrated in FIGS. 8and 9. Cap 34 includes internal cylindrical aperture 35 shaped toslidably fit over the circular distal end 26 of head 10 and to cover atleast a portion of the cylindrical peripheral surface 13 of head 10 ofthe wine bottle shaped implant of FIG. 1. The pliable sheet 24 in FIG. 8has a circular aperture 37 formed therethrough which is large enough toslide a selected distance up the conical tip of cap 34, in the mannershown in FIG. 8, but which is too small to slide over the cylindricalupper end 39 of cap 34. Consequently, the conical end 40 of cap 34functions to hold the sheet 24 in position against the hydroxyapatitecomposition 28 in the manner illustrated in FIG. 8. Further, a portionof the conical end 40 of cap 34 extends downwardly along surface 13 andpast end 26 so that after the composition 28 has solidified and cap 34is removed from head 10, a conically shaped space 41 (FIG. 8A) existsintermediate the solidified composition 28 and the upper portion ofsurface 13. When an artificial tooth 50 is subsequently attached to head10 using the internally threaded aperture 19 formed therein, the lowerportion of tooth 50 can include a cylindrical aperture 51 which slidesover the upper end of head 10 and covers distal end 26. As would beappreciated by those of skill in the art, either sample implants orimpression analogs of the head 10, 10A (FIG. 12) of the support member70 (FIG. 12) of each implant can be provided to a dental laboratory sothat the lower margins of an artificial tooth 50 can be perfectly sizedto extend into and completely fill the conically shaped space 41. Distalend 26 ordinarily is positioned at the gum line after the implant isinserted in an opening 38 formed in the alveolar bone. Accordingly, theportions of the artificial tooth 50 extending into space 41 extend belowthe gum line of the patient.

FIG. 10A illustrates a normal, healthy alveolar bone 52 supporting anincisor tooth 53. In FIG. 10B, the bone 52 has receded due to age orother factors. In FIG. 10C, tooth 53 has been removed; a cylindricalaperture 54 has been drilled or otherwise formed in the bone 52; animplant has been inserted in aperture 54; a malleable hydroxyapatitecomposition 28 has been packed into aperture 54, around the implant, andagainst the bone 52; a layer of pliable material 24 has been attached tohead 10 with the head 21 of a healing cap and extends over thehydroxyapatite composition 28; and, the gum tissue has been positionedover material 24. After the bone 52 grows into the hydroxyapatitecomposition 28 and the composition 28 solidifies, the healing cap andmaterial 24 are removed, and an artificial tooth is attached to head 10.The hydroxyapatite composition applied to the implant and bone 52 inFIG. 10C is used to augment or build the bone 52 back up to a shape anddimension resembling or duplicating its original normal shape anddimension illustrated in FIG. 10A. A particular advantage of the dentalimplant methodology of the invention is that it permits hydroxyapatitecompositions to be used to augment and enlarge existing alveolar bonestructure while at the same time facilitating the anchoring of animplant to alveolar bone. To facilitate the anchoring of an implant inthe existing alveolar or basal bone, indents or grooves can be formed inthe bone or in the surface of the implant to receive hydroxyapatite orother material used to fill or pack into or around the alveolar or basalbone and the implant.

In FIG. 10D, the tooth 53 has been removed from the alveolar bone 52 ofFIG. 10B and a circular drill has been used to remove some of the bone52 to form a cylindrical anchor peg 56 which is shaped and dimensionedto be slidably received by the involute 15 of the implant of FIG. 1 inthe manner illustrated in FIG. 10E. After involute or hollow 15 is slidonto peg 56, malleable hydroxyapatite composition is packed around thebody 11 and head 10 of the implant and the head 21 of the healing cap isused to attach pliable material 24 to head 10. If desired,hydroxyapatite composition 28 can also be inserted in hollow 15 beforehollow 15 is slid onto peg 56. One the hydroxyapatite composition hassolidified, the healing cap and material 21 are removed, and anartificial tooth is attached to head 10. The bone 52 illustrated inFIGS. 10D and 10E includes a nerve 65.

In FIG. 10F, the tooth 53 has been removed from the alveolar bone 52 ofFIG. 10B and shape of the ridge 64 of bone 52 has not been altered. Animplant has been placed on ridge 64. The implant includes head 61, body62, and arch or U-shaped aperture 63. Aperture 63 is shaped anddimensioned to conform to and slide on to ridge 64 in the mannerillustrated in FIG. 10F. The implant of FIG. 10F can be formed by makinga mold of ridge 64 and using the mold to eventually produce an implantwith an aperture 63 which will conform to ridge 64. Various techniquesfor making a mold of ridge 64 and using the mold to produce a duplicateof the ridge or to produce a shape which will conform to the ridge 64are well known in the art and will not be discussed herein. After theimplant of FIGS. 10F and 11 is slidably inserted on ridge 64 in themanner shown in FIG. 10F, malleable hydroxyapatite composition ispressed against and molded around against the implant and bone 52 andcovered with a layer 24 which is secured to head 61 by head 21 of thehealing cap illustrated in FIG. 1. The externally threaded end 20 of thehealing cap is rotated into internally threaded aperture 67 formed inthe upper end of head 61. If desired, an aperture(s) 68 can be formedthrough body 62 to permit a screw(s) to pass through the aperture 68 andinto the bone 52 to secure the implant to the bone 52. In addition, aslot, indicated by dashed lines 66 in FIG. 10F, can be cut through ridge64 to receive a panel 69 which is attached to arch 63 in the positionindicated by dashed line 70.

FIGS. 12 to 15 depict apparatus using in a molding method which is usedin conjunction with the implant apparatus and methodology of theinvention. In FIG. 12, an implant having a head 10A and bottom 11A isheld in position in opening 79 formed in alveolar bone by a solidifiedhydroxyapatite composition 28. Composition 28 solidified when thesurrounding alveolar bone 80 grew into the composition 28 in opening 79.Head 10A has a conical head which tapers upwardly from body 11A towardthe gum tissue 81. Head 10A has outer smooth continuous surface 13A.Body 11A includes outer smooth continuous surface 14A. Frustoconicalsupport member 70 is attached to head 10A. Sacrificial frustoconicalcoping 71 is slid over member 70. Sacrificial frustoconical coping 74 isslid over member 73. If desired, copings 71 and 74 can be metal and notbe sacrificial. Member 73 is attached to the head 10A (not shown) ofanother implant (not shown) in the alveolar bone 80. Rubber, silicone,or some other acceptable material is used to form a negative mold 72extending over and around copings 71 and 74 in the manner shown in FIG.12. The use of such molding materials in dentistry is well known andwill not be discussed herein. The negative mold includes upstandinghollow conical member 85; frustoconical hollows 83 and 84 which conformand adhere to copings 71 and 74, respectively; and, surfaces 86 and 87which conform to gum tissue 81. When the negative mold 72 is removedfrom members 70 and 73, copings 71 and 74 are removed with and areimbedded in the mold 72.

After mold 72 has set and is removed from members 70 and 73 and from thepatient's mouth, mold 72 is used to make a positive stone mold 78. Thisis, as is well known, accomplished by inverting mold 72, place mold 72in a container which circumscribes mold 72, and by pouring a stone moldslurry into sacrificial copings 71 and 74 and over surfaces 86 and 87.After the stone mold slurry hardens to form mold 78, the mold 78 andmold 72 are heated until mold 72 melts and flows off of stone mold 78,or, mold 72 can simply be peeled off of the hardened stone mold with orwithout copings 71 and 74. The positive stone mold 78 which remainsreplicates the gum line 81, support members 72 and 73, and the upperportion of each head 10A as shown in FIG. 12. The stone mold 78 alsoreplicates 82A the conical groove or detent 82 formed around the upperportion of each implant head 10A. In FIG. 14, each conical groove 82 hasa shape and dimension equal to the shape and dimension of conical groove82 in FIG. 14. Also, in FIG. 14, the portions of the stone mold whichreplicate frustoconical members 70 and 73 are not visible because newsacrificial copings 71A and 74A have been slipped over said portions ofthe stone mold (or the copings 71 and 74 which were originally used inthe mouth to make mold 72 can remain on said portions of the stonemold). While the shape and dimension of each coping can vary, in FIGS.12 to 14, each coping 71, 74, 71A, 74A is of equivalent shape anddimension. The shape and dimension of each support member 70 and 73 canalso vary as desired. In FIG. 12, however, each frustoconical supportmember 70 and 73 is of equal shape and dimension.

In FIG. 14 a pontic comprised of frustoconical support member 77 andribs 75 and 76 has been constructed above the upper surface 90 of stonemold 78. The pontic interconnects sacrificial copings 71A and 74A and ispositioned adjacent surface 90. The pontic is typically constructed fromwax, but any other desired material can be utilized. Once theconstruction of the pontic is completed, the sacrificial bridge supportof FIG. 14 is removed from mold 78 and mold 78 is discarded, or, mold 78is retained for use in subsequent porcelain work. After the sacrificialbridge support is removed from mold 78, its shape and dimension andappearance is identical to that of the finished metal bridge supportpictured in FIG. 15.

In the next step of the molding process, the sacrificial bridge supportis submersed or "invested" in a stone mold slurry and, before or as theslurry hardens, a small escape channel is formed which leads from thesacrificial bridge support through and to the upper surface of theslurry. After the stone mold slurry hardens, it is heated to melt thewax pontic and the sacrificial copings 71A and 74A. The melted wax andmelted materials from the copings 71A and 74A flows out of the stonemold through the escape channel. After all of the melted material flowsout of the stone mold, a hollow exists in the stone mold which is anegative of the sacrificial support bridge of FIG. 14 and of the bridgeof FIG. 15. The investment molding process is continued by pouringmolten metal through the escape channel into this hollow and allowingthe metal to harden. After the metal hardens, the finished supportbridge of FIG. 15 has been formed in the stone mold. The stone mold isbroken away from the bridge to free the finished bridge from the mold.Porcelain or another desired material is placed on the bridge supports74B, 77A, and 71B to build artificial teeth on the bridge. Ordinarily, asingle artificial tooth is built on each bridge support. Afterartificial teeth are constructed on the bridge supports, the bridge isinserted in the patient's mouth by placing hollow support 71B overmember 70 and by placing hollow support 74B over member 73. Supports 74Band 71B can be glued or otherwise affixed to members 73 and 70,respectively.

A method of removably attaching a bridge support 74B and artificialtooth 91 to a member 73 is illustrated in FIG. 16. In FIG. 16 a fastener94 is inserted into aperture 92 and threaded into internally threadedaperture 93 in member 73. Precise alignment of apertures 92 and 93 isnot required because the diameter of aperture 92 is slightly larger thanthat of aperture 93. The undersurface 95 of fastener conforms to andbears against a portion of conical surface 96 to prevent the tooth 91from moving in the directions of arrows B. When fastener 94 is removedfrom apertures 92 and 93, coping 74B can be pulled upwardly off of andfree from support member 73.

In FIG. 16, the upper distal end 26A of head 10A contacts the bottom ofsupport member 73. The outer peripheral conical surface of head 10A iscontiguous with and lies in a common conical plane with the outerconical surface 13A of head 10A. Coping 74B conforms to surface 13A andto the outer conical surface of member 73 so that coping 74B slidablyengages and fits said conical surfaces in the manner illustrated in FIG.16. The co-planar relationship of the conical surface of member 73 andthe conical surface 13A of member 10A is important in the practice ofthe invention because it enables coping 74B and tooth 91 to extendsealingly downwardly below the gum line, i.e. to extend downwardly belowend 26A.

Members 70 and 73 can be fabricated from metal or from plastic, rubber,copolymer, polymer, composites, or any other desired material, as canthe sacrificial copings 71, 74, 71A, 74A.

The implant method and apparatus of the invention have severaladvantages. First, since the opening which is formed in the bone toreceive the implant does not have to conform to the shape and dimensionof the implant, special drills are not necessary when the opening isformed in the alveolar or basal bone to receive the implant. Second,drilling an opening in the bone which is larger than and does notconform to the shape and contour of the implant decreases the amount ofheat generated during the drilling process. This is important becausebone is damaged when exposed to heat in excess of 130 degrees centigradefor one minute or more. Conventional implants require that a cylindricalopening be drilled in the bone. Drilling such openings requires the useof internally irrigated slowly rotating burrs and is more likely togenerate heat which damages the bone adjacent the cylindrical opening.When an opening is drilled for the implant of the invention, a higherspeed externally irrigated burr can be utilized. Third, the implant ofthe invention permits non-resorbable hydroxyapatite to be utilized tofill in the opening around the implant. The non-resorbablehydroxyapatite produces a strong, tough structure which is less likelyto have saucerization. Saucerization occurs when bone is lost fromaround the implant due to stress or bacterial invasion. This use ofnon-resorbable hydroxyapatite is particularly advantageous when a boneridge which has receded is being augmented to duplicate the originalshape and size of the ridge. Fourth, the lateral insertion of an implantin the manner illustrated in FIGS. 6 and 7 is useful in the case where atooth has been missing for some time and adjacent teeth have migratedinto and partially filled the space of the missing tooth. When thisoccurs, conventional implants either are forced to be so small that theyare weak or are prevented from being utilized due to the small size ofthe space remaining between the adjacent teeth. The implant of FIGS. 1and 8 solves this problem because it has a large base with a thin neckwhich can extend between the remaining adjacent teeth. Fifth, theimplant method of the invention covers the junction between a supportmember 70 and the head 10A (FIG. 12) of the implant. In conventionalimplants, this junction is exposed to oral fluids and can corrode andfail. Further, dentists often do not screw or otherwise install member70 snugly against the top of head 10A, leaving a septic gap. Sixth, theimplant of FIGS. 1, 8 and 12 can be long or short and still provide alarge outer surface area for anchoring the implant in the alveolar orbasal bone.

As would be appreciated by those of skill in the art, the implantmethodology described above in connection with dental implants can beutilized to carry out implants in bone throughout the body. For example,in FIG. 17, the "ball" at the top of femur 100 has been removed and anoversized opening 101 has been formed in the top of femur 100. Implant103 is inserted in opening 101. The lower portion of implant 103 is thebody thereof and the upper portion of implant 103 (the portion nearestartificial "ball" 105) is the head of the implant 103. Each implant inthe prior art and illustrated herein includes a lower portion, or body,and an upper portion, or head. A hydroxyapatite (HA), hydroxyapatitecement (HAC) or other composition 102 is packed around implant 103 tosecure implant 103 in opening 101. An internally threaded cylindricalaperture (not visible) is formed in implant 103 to receive theexternally threaded end 104 of an artificial "ball" 105. It isadvantageous to form opening 101 by laterally cutting or drilling intothe top of femur 100 in the manner illustrated in FIG. 6. This reducesthe amount by which the femur has to be laterally displaced away fromthe hip socket during formation of opening 10, thus reducing trauma tosurrounding nerves, muscles, blood vessels and soft tissue.

In FIG. 18, the opening 108 in bone 107 and the implant 106 are shapedand dimensioned such that when implant 106 is laterally slid intoopening 108, a mechanical lock is formed and implant 106 cannot beremoved from opening 108 in the direction of arrow C. Similarly, opening108 and implant 106 can be formed such that implant 106 is inserted inopening 108 in the direction directly opposite that of arrow C and isrotated 90 degrees about an axis parallel to arrow C such that afterimplant 106 is so rotated, it cannot be displaced out of opening 108 inthe direction of arrow C because the longer dimension of implant 106 hasbeen turned to a position similar to that shown in FIG. 18 under theinwardly extending lips 109 and 110 of opening 108.

The opening 108 illustrated in FIG. 18 can be formed and an implantinserted in opening 108 which flares outwardly like implant 106 butwhich can be readily withdrawn from opening 18 in the direction of arrowC. The implant is anchored in opening 108 by packing HA, HAC, or anothercomposition in opening 108 and around implant 106.

The composition 102 used to pack around an implant 103 can includemagnetic fibers and have a viscosity which permits the fibers to alignwhen a magnetic force is applied to the composition. The composition 102can also, in combination with the magnetic fibers or in place of themagnetic fibers, include fibers which do not respond to the magneticforce.

As noted earlier, active compositions can be utilized in combinationwith or in place of hydroxyapatite compositions. Such activecompositions, or tissue growth factors, can be intermixed withhydroxyapatite or other materials utilized as packing around an implant,can be coated on an implant 103, or can be inserted in situ intermediatethe implant 103 and opening 101 to cause, for example, the bone to growback inwardly toward the implant. In the event implant 103 is coatedwith a bone growth factor or a bone growth factor is inserted in situintermediate an implant 103 and opening 101 in the bone, positioningmeans can be utilized to maintain implant 103 in its desired position inopening 101 until bone ingrowth contacts implant 103 and maintains it inposition. The positioning means can also be utilized to maintain animplant in position until a filler material is packed in opening 101around the implant to anchor the implant in position. Such positioningmeans can consist of a collar or template which fixedly and/orresorbably contacts or supports implant 103 and is anchored tosurrounding bone or other tissue. The positioning means can also consistof a putty or gel which is packed around the implant 103 to maintain itin position while bone grows into the putty or gel and to the implant oruntil the putty or gel sets up. Once bone ingrowth secures implant 103in its desired position, the collar or template which is used to supportthe implant is removed or is resorbed. Resorption of the collar orimplant can occur according to the natural physiological process of thebody or can be triggered and/or facilitated by external means such asheat, electricity, enzymes injected into tissue, etc.

By way of further example of the template just referred to, an implantto replace a missing first molar in the lower jaw of a patient iscarried out as follows. First, the space between the second premolar andthe second molar which bounded the missing first molar may be laserscanned or an impression taken to define the space so that the shape anddimension of the tooth which will fill the space can be defined. Animpression is taken of the lower teeth and a plaster model of the lowerteeth is made using well known molding techniques. This plaster model,as does the patient's mouth, includes on open spot which at one time wasoccupied by the patient's missing first molar. A model is made of theartificial tooth which will be mounted on the implant. The model isproperly positioned in the open spot in the plaster model and aimpression is made of the plaster model using plaster, plastic or anyother desired material. This plastic model will fit over and conform tothe lower teeth in the patient's mouth. An opening is formed through theplastic model and an externally threaded screw or other attachment meansis attached through and extends downwardly from the plastic model sothat the implant which will be utilized in the mouth of the patient canbe detachably secured to the externally threaded screw. The externallythreaded screw positions the implant in the exact desired orientation,both laterally and vertically, with respect to the plastic model andwith respect to the opening formed in bone in the patient's mouth (orwith respect to bone in the patient's mouth on which the implant isset). An oversized opening 27 (FIG. 3) is drilled in the alveolar bone.The bottom of the opening is prepacked with a selected amount ofhydroxyapatite or other composition. The implant 11 is threaded onto theexternally threaded screw in the plastic model and the plastic model isfit over the crowns of the patient's lower teeth to force the implant 11into the opening 27 and force the hydroxyapatite composition up andaround the implant 11. Openings can be formed in and through the plasticmodel to permit hydroxyapatite composition to be added to or removedfrom opening 27. Or, in the event implant 11 is simply coated with abone or tissue growth factor, openings need not be formed through theplastic model to permit access to opening 27 because the plastic modelpositions the implant 11 in the exact desired location in opening 27 andmaintains the implant 11 in that position until the tissue growth factorcauses an outgrowth of new bone from opening 27 which contacts andanchors implant 11 in position. The coating of bone or tissue growthfactor can occur just prior to insertion of the implant, after theimplant is inserted, or well prior to insertion of the implant. Afterthe implant 11 is anchored by the growth of new bone toward the implant,the externally threaded screw is turned out of the implant, the plasticmodel is removed and an artificial tooth can be threaded into orotherwise attached to the anchored implant 11. After (of before, ifdesired) the artificial tooth is attached to implant 11, a tissue growthfactor can be applied around the implant to the surface of the implant,to the surface of bone around implant 11, or to gum tissue to promotethe growth of gum tissue over the surface of the bone and adjacent theartificial tooth.

Growth factors can be utilized to induce the growth of "hard tissue" orbone and "soft tissues" like ectodermal and mesodermal tissues. As usedherein, the term growth factor encompasses compositions and livingorganisms which promote the growth of hard tissue, such as bone, or softtissue in the body of a patient. The compositions include organic andinorganic matter. The compositions can be genetically produced ormanipulated. The living organisms can be bacteria, viruses, or any otherliving organism which promote tissue growth. By way of example and notlimitation, growth factors can include platelet-derived growth factor(PDGF), epidermal growth factor (EGF), fibroblast growth factor(acidic/basic)(FGF a,b), interleukins (IL's), tumor necrosis factor(TNF), transforming growth factor (TGF-B), colony-stimulating factor(CSF), osteopontin (Eta-1 (OPN), platelet-derived growth factor (PDGF),interferon (INF), bone morphogenic protein 1 (BMP-1), and insulin growthfactor (IGF). Recombinant and non-recombinant growth factors can beutilized as desired. Bacteria or viruses can, when appropriate, beutilized as growth factors. For example, there is a bacterialhydrophilic polypeptide that self-assembles into a nanometer internaldiameter pore to build a selective lipid body. Various enzymes can beutilized for the synthesis of peptides which contain amino acids thatcontrol three-dimensional protein structure and growth. Growth factorscan be applied in gels or other carriers which regulate the rate ofrelease of the growth factors and help maintain the growth factors, andthe carrier, at a desired location in the body. Time release capsules,granules, or other carriers containing growth factor can be activated bytissue pH, by enzymes, by ultrasound, by electricity, by heat, byselected in vivo chemicals or by any other selected means to release thegrowth factor. The carrier can be resorbable or non-resorbable. Or, thegrowth factor itself can be activated by similar means. Either thecarrier or the growth factor can mimic extracellular fluid to controlcell growth, migration, and function. The growth factor can beadministered orally, systemically, in a carrier, by hypodermic needle,through the respiratory tract, or by any other desired method. Thegrowth factor can also be administered into a capsule or other man-madecomposition or structure placed in the body. While administration of thegrowth factor is presently usually localized in the patient's body,circumstances may arise where it is advantageous to distribute a growthfactor throughout the patient's body in uniform or non-uniformconcentrations. An advantage to growth factors is that they can often,especially when in capsule form or in some other containment system, beinserted to a desired site in the body by simply making a small incisionand inserting the growth factor. The making of such a small incisioncomprises minor surgery which can often be accomplished on anout-patient basis. The growth factors can be multifactorial andnonspecific.

A variety of collagen materials can be used alone and in combination(Types 1 to 12) to form a containment sock, pocket or other structurefor a growth factor, which structure may have useful features ofcontrolled degradation and porosity for tissue reconstruction. Otherknown naturally occurring materials such as biopolymers, crosslinkedprotein scaffolds, and gels can be used alone or in combination witheach other or with any other material to form a containment system forhydroxyapatite or other tissue augmentation materials. A containmentpocket or other structure can be formed with synthetic organic materialssuch as polymers or plastics, with natural inorganic materials (e.g.,hydroxyapatite and other ceramics), with organic materials (e.g.,biopolymers), or with synthetic inorganic materials.

Possible polymers usable in a pocket or other containment structureconstructed in accordance with the invention include, withoutlimitation, poly (Amides), poly(Esters), poly(Orthoesters),poly(Anhydrides), poly (Ureas), poly(Orthoesters), poly(Anhydrides),poly(Ureas), poly(Alkyl 2-Cyanoacrylates), poly(Dihydropyrans),poly(Acetals), poly(Phosphazenes), and poly(Dioxinones). Each of theforegoing polymers is biodegradable in natural systems by undergoing ahydrolytic, enzymatic, or other breakdown or degradation and, as such,is capable of providing biodegradable matrices, scaffolds and otheruseful structures of a containment structure. Examples of biodegradablepolyamides include glutamic acid, glutamic acid/leucine, biodegradablenylon, glutamic acid/ethyl glutamate, hydroxyalkyl-L-glutamine, andcollagen. Examples of biodegradable polyesters include D, L lactic acid,glycolic acid/lactic acid, L-lactic acid, caprolactone/D,L lactic acid,diglycolic acid/transcyclonhexanedimethanol, and polyesterhydrogels.

In one embodiment of the packing material 102 used in the invention,hydroxyapatite is mixed with a biodegradable polymer, with or without agrowth factor impregnated therein, to provide a composition whichresists penetration by epithelial tissues but which promotes growth ofadjacent bone or soft tissue structure.

In a further embodiment of the invention, a pocket or other containmentstructure is fabricated from a microporous material containing a drug orother agent in its pores which promotes the growth of living tissue. Thepore sizes can be in the range of 25 to 400 microns, or can have anydesired size. The containment structure can be positioned in an opening101, adjacent selected soft tissue or bone, or at any other location inthe patient's body.

In another embodiment of the invention, hydroxyapatite or another tissueaugmentation material is mixed with a material to produce a mixturewhich is sensitive to ultraviolet light and which hardens and sets afterbeing dispensed at a desired location intermediate the tissue andunderlying bone. UV light is delivered by fiber optic means to thelocation at which the augmentation material is dispensed intermediatetissue and underlying bone. The UV light promotes the hardening orsetting up of the tissue augmentation material.

In still another embodiment of the invention, a volume of tissueaugmentation material is provided with a coating which resists migrationfrom the tissue augmentation material of tissue augmentation drugs orother growth factors or materials. The coating can be biodegradable andbreak down over time.

The hydroxyapatite (HA) and hydroxyapatite cement (HAC) compositionswhich can be utilized to pack around implants in accordance with theinvention are inorganic, crystalline materials. The hexagonal rhombicprism structure and calcium and phosphate composition of HA's and HAC'sare very similar to the natural ceramic hydroxyapatite mineral thatmakes up the inorganic portion of bone and teeth. HA's and HAC's arebioactive and interact with bone and teeth by forming a directphysicochemical bond with these hard tissues. Consequently, HA's andHAC's are osteoconductive and initiate bone ingrowth. HA's and HAC's canalso harbor osteoinductive material like osteocalcin which helps formnew bone cells. A distinct advantage of HAC's is that they can, whilestill in a relatively low viscosity state, be interposed between animplant and opening in the bone to readily conform to implant and bonesurfaces. Neither HAC's or HA's generate any appreciable heat when usedto pack around an implant. HAC's and HA's can be mixed with bodilyfluids.

HAC'S, HA's, growth factor compositions, and other packing compositionsused to pack around an implant can be formulated to expand after beinginserted intermediate an implant and surrounding bone. Such expansion isadvantageous because after an opening is cut in bone, the bone adjacentthe opening tends to shrink "away" from the opening, enlarging theopening. By way of example, an HAC packing composition can be formulatedto expand by intermixing a gas generating material or a material with athermal coefficient of expansion with the packing composition. The gasgenerating material forms pores in the packing composition and causes itto expand. The gas generated is preferably carbon dioxide, nitrogen, oranother inert gas is preferred. The gas generating or expandablematerial can be resorbable. If desired, the packing composition can beaerated with a gas before it is inserted in an opening to anchor animplant in place. Polyethylene has a coefficient of thermal expansion ofabout 0.00018 per degree Centigrade. Polyethylene or another polymermaterial with a preferred coefficient of thermal expansion can beutilized as a component in the packing composition. Or, the packingcomposition can include a liquid component which expands when the liquidcomponent sets and solidifies.

In one embodiment of the invention, a dental implant and crown aredesigned to custom fit in the alveolar bone and efficiently dissipateocclusal stress generated during use of the crown to chew food. Implantsother than dental implants can also be designed using the followingprinciples.

A ruler, X-ray, laser scanner, impressions of the teeth and jaws, orother means are used to define the shape and dimension of the space tobe occupied by the artificial crown which is attached to the implant andto define the shape and dimension of the alveolar bone in or on whichthe implant is to be positioned. A force diagram can be generated whichdefines how the roots of each original tooth in the mouth of anindividual dissipate the stresses generated on the tooth during chewingand/or biting. Similarly, a force diagram can be generated defining anoptimal root design for uniformly dissipating stress into alveolar bone,for dissipating more stress into stronger areas of the alveolar bone,etc. Such an optimal root design is ordinarily arrived at with the useof a computer and is important because many dental problems derive fromthe interaction of teeth with bone surrounding the teeth. The quality ofthe bone adjacent teeth varies. Some bone can withstand occlusal stressbetter than other bone. Some areas of the jaw have more alveolar boneadjacent to and supporting a tooth than do other areas of the jaw.Another factor which can be utilized to determine the optimal shape anddimension of the implant (and crown) is the material used to fabricatethe implant.

An eight foot long two inch by four inch piece of lumber better resistsa force which is applied perpendicular to the length of the lumber andto a two inch side of the lumber than it resists the same force appliedto a four inch side of the lumber and perpendicular to the length of thelumber. Similarly, the orientation of an implant root with respect tothe surrounding bone can have a bearing on the ability of the root andthe implant to resist a force vector which is applied to the implant ata particular point and at a particular orientation. Therefore, theorientation of the roots of the implant is another factor which can betaken into consideration by a computer in designing the optimal implant.Still another factor is the shape and position of the tooth (or teeth)which opposes and will contact the crown on the implant after theimplant and crown are anchored in alveolar bone.

In the dental implant art, the "Theory of Available Bone" teaches thatimplants are customized to fit in existing bone. The preferred method ofthe invention directly contradicts the Theory of Available Bone becausethe method of the invention teaches optimizing the effectiveness of animplant by first defining the optimal shape and dimension and thedensity or other physical properties of the bone which should beavailable to anchor the implant. In the method of the invention, if asufficient volume of bone is not available, additional bone volume isgenerated by packing HA, HAC or some other material on existing bone togenerate new bone, by using growth factors to generate new bone, or byusing any other desired procedure to generate new bone. If the densityof the existing bone is not sufficient, existing bone can be removed andreplaced with HA, HAC, or another desired composition which will havethe desired density or other physical properties or which will cause newbone to grow which has the desired density or other physical properties.HAC can form bone consisting of about 77% by weight mineral composition.This is denser than natural bone and can be particularly desirable informing new bone in the posterior bone areas of the mouth. The bone inthe posterior areas of the mouth supports the molars. Such bonetypically is less dense than the bone in the anterior areas of themouth. Bone in the anterior areas of the mouth supports incisors. Inaddition, if the existing bone volume is too great, bone can be removed;for example, a bone spur could be removed. Consequently, the method ofthe invention propounds a "Theory of Optimal Bone--Optimal Implant"design and implementation in which existing bone structure can bealtered and the design of each implant can, if appropriate, differ fromthe design of the other implants in a patient's mouth in order to insurethat a implant is formed which effectively distributes the occlusalforces generated on the implant and bone during use of the teeth. Anydesired set of criteria or parameters can be used in defining thedesired volume, density, and other physical properties of the bone usedto support an implant. For example, but not by way of limitation, thevolume of bone typically will approximate the volume of the originalbone structure which is (or was) present in the mouth when the patientis a young adult. Such bone volume is readily measured or, in the eventportions of the original bone structure have been lost, can be readilyapproximated. The desired density of the bone typically presently willbe at least equal to the density of the original bone structure.Further, by way of example, the largest possible bite force is notnecessarily produced in a direction which is perpendicular to theocclusal plane. The posteriorly and medially directed forces generallyreach higher values than the anteriorly and laterally directed forces,respectively.

A computer can also be utilized to determine the position of the implantat which the implant optimally distributes stresses into surroundingbone. The optimal position of the implant can be determined based uponselected factors included, but not limited to, the morphology of thesurrounding alveolar bone, the size and stability of adjacent teeth,etc. For example, once the shape and dimension of an implant isdetermined, the implant may better distribute stress if it is positionedin (or on) alveolar bone closer to a first adjacent tooth than to asecond adjacent tooth because the quality of bone is better near thefirst adjacent tooth.

The shape and dimension of the crown can depend on factors including,but not limited to, the type of tooth (a molar has more cusps than anincisor), the size of the space in the patient's mouth in which thecrown must fit, and the material used to fabricate the crown (a strongermaterial might enable portions of the crown to be smaller than if aweaker material is used).

After the shape and dimension of the implant and crown are defined, theimplant and crown can be manufactured using computerized equipment. Acomputerized lathe system could, for example, be used to cut the implantfrom a piece of metal and to cut, mold, or otherwise form the crownwhich is secured to the implant. Or, the implant and crown can beproduced utilizing any desired conventional production methods. Afterthe implant and crown are produced, the implant is anchored at thedesired position in the alveolar bone using any of the proceduresearlier described. For example, on opening can be formed in the alveolarbone, the implant inserted in the opening, and HA or other materialpacked around the implant to anchor the implant in the opening. Thecrown can be attached to the implant before or after the implant issecured in the alveolar bone.

Locating an implant in the upper molar area of the mouth can bedifficult because the alveolar crestal bone is thin and adjacent thesinuses. Consequently, the mass or volume of available bone in which toanchor an implant is marginal. In order to position an implant in thealveolar crestal bone in the upper jaw, a first prior art procedure wasdeveloped. In this first prior art procedure, the alveolar bone isscored along a rectangular line. The portion of the alveolar bonecircumscribed by the score line, referred to herein as the "pad", isthen carefully pushed inwardly to avoid tearing the Schneiderianmembrane and to form a rectangular opening through the alveolar bone. Ablock-shaped base is inserted through the rectangular opening in thealveolar bone to a position in which the base contacts or is adjacentthe pad. The area around the base is filled with loose hydroxyapatitematerial and the opening in the alveolar bone is covered with the gum oranother material to permit the hydroxyapatite to harden. Six to ninemonths later, the gum is reopened to anchor an implant and/or artificialcrown in the block-shaped base.

The foregoing first prior art procedure for positioning an implant inthe molar alveolar bone has several disadvantages. First, avoidingrupture of the Schneiderian membrane is sometimes difficult, which meansthere is an increased risk that infection in the patient's sinus willspread into the hydroxyapatite or other areas of the graft. Second, theblock-shaped base must be covered, or buried, while the hydroxyapatitehardens. This means a second later operation is required to insert anartificial crown or implant in the base once the hydroxyapatite hardens.Third, the insertion of an implant is postponed for six to nine monthswhile the sinus graft heals. Fourth, the block-shaped base tends toshift out of its desired position adjacent the pad, which makes itdifficult, if not impossible, to properly position the implant when thegum is later reopened and the implant is inserted in the block-shapedbase.

A second prior art procedure, termed the lateral sinus lift procedure,was developed to overcome shortcomings in the first procedure discussedabove. In this second prior art procedure, a cut is made through themaxilla, exercising care not to rupture the Schneiderian membrane. Thecut forms a flap which is displaced, or lifted, laterally and upwardlyinto the sinus cavity, again without rupturing the Schneiderian membranewhich lines the sinus cavity. Avoidance of damage to the Schneiderianmembrane during the lateral sinus lift is important because rupture ofthe membrane permits the rapid spread of infection in the sinus cavity.In the event the Schneiderian membrane is ruptured, a resorbablecollagen pad is used to cover the rupture, or the rupture is otherwiserepaired. After the flap is lifted, the space intermediate the flap andthe alveolar crest is filled with porous hydroxyapatite. Six monthslater, an opening, i.e., an osteotomy, is carefully drilled through thealveolar crest and into the hardened hydroxyapatite. The opening closelyconforms to the shape and dimension of an implant which is fitted intothe opening.

The foregoing second prior art procedure for positioning an implant inthe molar alveolar bone has several disadvantages. First, avoidingrupture of the Schneiderian membrane is sometimes difficult, which meansthere is an increased risk that infection from the sinus will spreadinto the graft. Second, the incision through which the hydroxyapatite isinserted must be sealed. Third, the insertion of an implant is postponedfor six months while the sinus graft heals. This means a secondoperation is required to insert the implant. Fourth, the insertion ofthe implant requires the formation of an opening which closely conformsto the shape and dimension of the implant.

A third prior art procedure for positioning an implant adjacent thesinuses is similar to the second prior art procedure described above inthat a lateral sinus lift is also performed. However, in the third priorart procedure, after the lateral sinus lift is performed an opening iscarefully drilled through the alveolar crest. This opening conforms toand receives the upper portion of an implant. Since the alveolar crestis thin, the lower portion of the implant extends from the alveolarcrest into the space intermediate the alveolar crest and the flap ofbone bent inwardly during the lateral sinus lift. Hydroxyapatite is thenpacked between the alveolar crest and the flap of bone and is packedaround the implant.

The foregoing third prior art procedure for positioning an implant inthe molar alveolar bone has several disadvantages. First, avoidingrupture of the Schneiderian membrane is sometimes difficult, which meansthere is an increased risk that infection will travel from the sinusinto the graft. Second, gum tissue must be used to cover, or bury, theimplant while the hydroxyapatite solidifies. This necessitates a lateroperation to expose the implant to attach an artificial crown to theimplant. Third, the insertion of the artificial crown in the implant ispostponed for six months while the sinus graft heals. Fourth, theinsertion of the implant requires the formation of an opening whichclosely conforms to the shape and dimension of the implant.

One method of the implant of the invention facilitates the insertion ofan implant in the alveolar crest adjacent the atrophic posteriormaxilla. This method of the invention is illustrated in FIGS. 19 to 21.In FIG. 19, a retractor 114 is utilized to draw soft tissue away fromthe posterior maxilla 111. A drill or other tool is used to cut throughthe maxilla 111 to form a rectangular groove 130 defining a flap 112. Ifnecessary, the maxilla 111 can be scored along line 131 to facilitatethe inward and upward bending of flap 112 into sinus cavity 121 to theposition illustrated FIG. 20. An opening 132 is formed through thealveolar bone 117. An implant 119 is inserted through opening 132 intothe area intermediate flap 112 and the alveolar bone 117. Hydroxyapatitecement (HAC) 120 is used to pack around implant 119 intermediate flap112 and bone 117. The HAC is inserted through opening 132 or through theopening formed in the maxilla when flap 112 is bent upwardly andinwardly into the sinus cavity 121. If desired, the Schneiderianmembrane can be scraped away from and off of the bone to facilitatebonding of the HAC with the bone. The HAC has a putty like consistencyand rapidly sets up and hardens, typically within 10 to 15 minutes. Whenthe HAC hardens, it seals the sinus cavity 121. Sealing the sinus cavity121 is critical because bacteria in the sinus cavity 121 which mayinvade the graft through a breach in the Schneiderian membrane aresealed in the sinus cavity. Consequently, the method of the inventionpermits the Schneiderian membrane to be cut through, enables an implantto be quickly placed adjacent the maxilla, and does not require theformation through the alveolar bone (or hardened HAC) of an openingwhich closely conforms to the implant being utilized. The orientation ofimplant 119 can, until HAC 120 hardens, be adjusted by canting ortilting implant 119 in opening 132 and in the area intermediate flap 112and bone 117. HAC is presently preferred in the practice of this methodof the invention because it includes hydroxyapatite and because itrapidly sets up. Any other desirable packing material can, however, beutilized in place of HAC. Various other packing materials are discussedearlier herein.

The method of the invention may enable an implant and crown to becompletely installed in one operation. In contrast to the prior artprocedures described above, the method of the invention does not requirethat an initial incision be made, be closed, and then be reopened at alater date to complete the implant procedure. In the method of theinvention, the implant and/or artificial crown attached to the implantcan extend through the gum into the mouth soon after an opening isformed through alveolar bone and after the Schneiderian membrane isruptured.

The method illustrated in FIGS. 19 to 21 can also be carried out withoutforming flap 112. In this procedure, opening 132 through the alveolarbone 118 is formed and HAC putty is packed between the maxilla 111 andother bone 133 bounding the sinus cavity 121. The implant 119 ispositioned in the HAC. If desired, the entire sinus cavity 121 can befilled with HAC or another packing material. Again, if desired, theimplant and/or artificial crown attached to the implant can extendthrough the gum into the mouth.

In another embodiment of the invention, genetically produced livingmaterial is used to form an implant in the bone of a patient. The DNAstructure of a patient is analyzed from a sample of blood or othermaterial extracted from a patient and a biocompatible tooth bud 122(FIG. 22) is produced. The bud 122 is placed in an opening 123 in thealveolar bone and packing material is placed around or on top of the bud122. The size of opening 123 can vary as desired. The packing around bud122 can comprise HAC 124, hydroxyapatite, blood, growth factors, or anyother desirable packing material. The bud 122 grows into a full growntooth in the same manner that tooth buds which are in the jaws ofchildren beneath baby teeth grow into full sized teeth. Instead of bud122, a quantity of genetically produced living material which causes bud122 to form in the alveolar bone can be placed at a desired position inthe alveolar bone such that bud 122 forms and grows into a full sizedtooth. Instead of forming an opening 123, a needle or other means can beused to simply inject the genetically produced living material into aselected location in the alveolar bone. As would be appreciated by thoseskilled in the art, genetically produced materials can be inserted inthe body to cause the body to grow, reproduce, and replace leg bone,facial bone, and any other desired soft and hard tissue in the body.

The HAC 120, 124 or other packing material used in the implant methodsof the invention can include BIODEL or other small polymer beads orcarriers of antibiotic materials.

As used herein, hydroxyapatite cement (HAC) is a cement composedentirely or in substantial part of calcium phosphate salts. HAC can becombined with water to form a dense paste which is applied and shapedintraoperatively. HAC sets in vivo in approximately 10 to 15 minutes toform a structurally stable implant composed of microporoushydroxyapatite. The calcium phosphate salts tetracalcium phosphate andanhydrous dicalcium phosphate are the primary components of HAC. Thesesalts react in water to isothermically form hydroxyapatite. After thecalcium phosphate salts in powder form are mixed with water, theresulting composition sets in about ten to fifteen minutes. Themicroenvironment in the set cement is saturated with calcium phosphatesalts. Hydroxyapatite precipitates in situ from this microenvironmentduring a reaction which typically takes from four to six hours.

A further embodiment of the invention concerns the integration of adental implant into the lower jaw of a patient. Portions of the bonecomprising the lower jaw are hollow and lined with marrow or other softtissue. A first small opening 134 (FIG. 3) can be formed through theoutside of the jaw and a second small vent opening can be formed throughthe inside of the jaw or elsewhere. A pressurized tube or other means isused to inject hydroxyapatite cement slurry through opening 134 into thehollow area in the lower jaw. The second opening serves as a vent whichpermits air or other material to escape from within the lower jaw whenhydroxyapatite cement slurry is injected in the jaw. If desired, thefirst opening can be made slightly larger than the tube used to injectHAC slurry into the jaw such that the first opening permits air or othermaterial in side the jaw to vent outwardly through the first openingwhile RAC slurry flows from the tube into the jaw. In this case, thesecond vent opening may not be required. An X-ray(s) can be taken of thejaw to insure that the desired areas of the lower jaw are filled withHAC slurry.

After the HAC slurry is injected into the jaw, the first and secondopenings are plugged with HAC putty, polyglycolic acid, bone wax, oranother desirable material. After the AC slurry which was injected intothe jaw hardens sufficiently, on opening can be made through thealveolar bone of the lower jaw and into the hardened HAC to receive animplant.

A HAC slurry injection method similar to the slurry injection methoddescribed above for the lower jaw can be used to inject HAC slurry intoa space between the sinuses and alveolar bone of the upper jaw. A smallaccess opening is drilled through the maxilla. Or, the Caldwell-Lucapproach can be utilized to gain access to the sinus through the nose.Once access is gained to the sinus, an instrument is used to score andrupture the sinus membrane so that HAC injected into the sinus cancontact and bond to the underlying bone. HAC slurry or another desirablematerial is then injected into the sinus through the opening with a tubeor by using other means. After the HAC slurry hardens, an opening can beformed through the alveolar bone and into the hardened HAC to receive animplant. HAC slurry, injectible hydroxyapatite, or other desiredmaterials--including but not limited to bioactive osteogenicmaterials--which facilitate the formation of new hard bone by the body,can similarly be injected into the "hollow" soft tissue inner marrowareas of the femur or other bones of the body through small holes formedin the bones.

Having described my invention in such terms as to enable those skilledin the art to understand and practice it, and having described thepresently preferred embodiments thereof, I claim:
 1. An insertibleimplant adapted for emplacement in a recess in bone, comprising(a) animplant member comprising a body and a head, said body being shaped anddimensioned and adapted to be emplaced and freely move from side-to-sidein the recess, said head being supported on said body; and, (b) amalleable composition adapted to be emplaced in the recess and extendover and contact said body, said composition(i) hardening to form astructure which fixes said body of said implant member in position inthe recess, (ii) extending from said bottom of said body upwardly overat least a portion of said body of said implant member, (iii)facilitating the formation of new bone-in the recess, and (iv)permitting said implant member to be tilted to deform said malleablecomposition and reposition said body of said implant member in therecess.
 2. The implant of claim 1 wherein said implant member includesliving material.
 3. An insertible implant adapted for emplacement inbone, comprising(a) an implant member comprising a body and a head, saidbody being shaped and dimensioned and adapted to be emplaced and freelymove from side-to-side in the recess, said head supported on said body;and, (b) a composition adapted to be emplaced in the recess and extendover and contact said body, said composition(i) hardening to form astructure which fixes said body of said implant member in position inthe recess, (ii) extending over at least a portion of said body of saidimplant member, (iii) facilitating the formation of new bone in therecess; and (c) a tissue growth factor.
 4. The implant of claim 3wherein said growth factor is a bacterium.
 5. The implant of claim 3wherein said growth factor is a virus.
 6. The implant of claim 3 whereinsaid growth factor is living material.
 7. The implant of claim 3 whereinsaid growth factor is recombinant.
 8. The implant of claim 3 whereinsaid growth factor is non-recombinant.
 9. The implant of claim 3 whereinsaid growth factor controls protein structure and growth.
 10. Theimplant of claim 3 wherein said growth factor controls cell growth. 11.The implant of claim 3 wherein said growth factor controls cellmigration.
 12. The implant of claim 3 wherein said growth factorcontrols cell function.
 13. The implant of claim 3 wherein said growthfactor is multifactorial and non-specific.
 14. The implant of claim 3wherein said implant member includes living material.
 15. An insertibleimplant adapted for emplacement in a recess in bone, comprising(a) animplant member comprising a body and a head, said body being shaped anddimensioned and adapted to be emplaced and freely move from side-to-sidein the recess, said head supported on said body; and, (b) a compositionadapted to be emplaced in the recess and contact said body, andcomposition including(i) a tissue growth factor, and (ii) a containmentstructure for said growth factor.
 16. The implant of claim 15 whereinsaid implant member includes living material.
 17. The implant of claim15 wherein said growth factor is a bacterium.
 18. The implant of claim15 wherein said growth factor is a virus.
 19. The implant of claim 15wherein said growth factor is living material.
 20. The implant of claim15 wherein said growth factor is recombinant.
 21. The implant of claim15 wherein said growth factor is non-recombinant.
 22. The implant ofclaim 15 wherein said growth factor controls protein structure andgrowth.
 23. The implant of claim 15 wherein said growth factor controlscell growth.
 24. The implant of claim 15 or wherein said growth factorcontrols cell migration.
 25. The implant of claim 15 wherein said growthfactor controls cell function.
 26. The implant of claim 15 wherein saidgrowth factor is multifactorial and is nonspecific.